The main objection of this project is to provide an accurate anatomical basis for understanding. The anatomico-radiological correlation of the cerebral vessels and the cerebral gyral and sulcal patterns, the knowledge of which are essential in the interpretation of cerebral angiograms. Even after emergence of C.T. Scan, it is important for neurosurgeons to pre-operatively have the three-demential concept of the living pathology of the brain, particularly the correlation of the lesion, the surrounding brain and vascular structures. Our research project will be carried out by: l) daily analysis of routine cerebral angiograms in both arterial and venous phases, 2) close comparison with routine CT scan performed as part of clinical work up, 3) dissection of normal and abnormal brains, 4) injection of cerebral vessels in post-mortem room, and 5) CT scanning of the formalinfixed brain in multidirectional planes. The latter will also be carried out in order to understand the gyral and sulcal patterns of the brains. These studies are to uncover hitherto unrecognized anatomico-radiological correlations of the brain. It should be emphasized that neither angiography nor CT scans of living patients are performed for research purposes. They are performed only when they are clinically indicated in the care of patients. Neither living human subjects nor tissues from living human subjects will be involved in this research project.